package Classic150;

import Tree.TreeNode;

public class 路径总和 {
    /*
        通过减法优化sum
     */
    public boolean hasPathSum(TreeNode root, int targetSum) {
        if (root == null) return false;
        if (root.left == null && root.right == null) return root.val == targetSum;
        return hasPathSum(root.left, targetSum - root.val) || hasPathSum(root.right, targetSum - root.val);
    }
}
